SELENIUM CONCENTRATION IN SPRING WHEAT AS INFLUENCED BY BASAL APPLICATION AND TOP DRESSING OF SELENIUM-ENRICHED FERTILIZERS

A multisite field experiment was conducted to study the effect of topd ressed Se-enriched Ca(NO3)(2) (CN) and basal applied NPK on the seleni um (Se) concentration in spring wheat (Triticum aestivum L.). Selenium was applied either through CN (at the rates of 0, 6.45, and 12.91 g S e ha(-1)) or NPK (5.83 g Se ha(-1)). Selenium concentration in wheat g rains increased consistently with increasing rate of Se-enriched CN or NPK. However, the superiority of Se-enriched CN over NPK in raising t he Se concentration in wheat grain depended on location and growth con ditions. At the same rate both methods of Se-application were found to be equally effective in raising the Se concentration of wheat grains. The Se concentration of grain was generally higher in the light textu red soils than in the medium to heavy textured soils. Without Se appli cation, the Se-concentration in wheat grain was about 16 mu g kg(-1) w hich is regarded insufficient to meet the Se requirement for Se in ani mal and human. Calcium nitrate enriched with 25 mg Se kg(-1) (6.45 g S e ha(-1)) increased the Se concentration in wheat grain to a desired l evel.